"The average age of most weight-loss programs' members is mid- to late 40s. And female. Recent re-targeted marketing efforts have increased the number of men in these programs."

"WW products range from branded groceries ... to a partnership with the meal kit company Blue Apron, unveiled Dec. 20."

Between the lines: It's not hard to see the appeal for Apple and Google in a future where a connected watch or phone holistically manages a diet plan. It could log physical activity and food intake, provide health data to doctors, and order the next round of delivery or restaurant meals — all in one connected ecosystem, paying fees at every step or in a bundle.

For consumers, that would bring convenience and simplicity, but also a financial price and a loss of privacy.

"If you zoom out into the future, and you look back, and you ask the question, 'What was Apple's greatest contribution to mankind?' It will be about health," Apple CEO Tim Cook told CNBC.

"We are democratizing it. We are taking what has been with the institutions and empowering the individual to manage their health."

The bottom line: Apple has already invested years to understand tech and build relationships with hospitals, doctors and regulators, reports Ina.

And Apple's work has already shown up in modest ways, like its fitness research lab, the ResearchKit that allows its products to be used in clinical studies, and the electrocardiogram in the latest Apple Watch.